Hearth construction for rotary oil burners



Sept. 29, 1936. M. A. PowERs 2,055,589

HEARTH CONSTRUCTION FOR ROTARY OIL BURNERS Filed Feb. 18, 1932 2 ShieeiS-Sheeb l N M www A. @Mw/mim n G YQ M f//s Hrw/gms sx N Sept. 29, 1936. M A POWERS 2,055,589

HEARTH CONSTRUCTION FOR ROTARY OIL BURNES Filed Feb. 18, 1952 2 Sheets-Sheet 2 Patented Sept. 2,9, 1936 UNITED STATES .PATENT oFFicE Milton A. Powers, Detroit, Mich., assignor to The Timken-Silent Automatic Company, Detroit, Mich., a corporation of Michigan Application February 18, 1932, Serial No. 593,741

13 Claims.v

My invention relates to hearth construction for rotary oil burners, particularly rotary burners of the type wherein both ignition and combustion take place adjacent to a wall or hearth ring disposed around the periphery of the hearth. The invention has for its principal object a hearth construction that provides a protected zone for initial ignition of the fuel and propagation of the flame around the entire periphery of the hearth 1o and which, at the same time, provides a sulcient draft and supply of air around the entire hearth to support combustion after initial ignition and propagation of the ame.

This application is a continuation in part of my application Serial No. 324,817, filed December 10, 1928, for Rotary oil burner and combustion chamber therefor.

The invention consists principally in providin a rib or wall around the periphery of the hearth,

and in providing said wall with an inwardly overhanging ledge or flange, forming a protected annular space for ignition and propagation of the flame. A further modificationv of the invention consists in providing said ledge with a multiplicity of recesses or openings through which the air draft passes. such'recesses preferably extending not more than half the distance from the front or inner edge of said ledge to the upstanding wall or rib.

' 30 The invention further consists in the hearth for rotary oil burners and in the parts, and combinations, and arrangements of parts hereinafter described and claimed.

lin the accompanying drawings, which form part of this specification and wherein like symbols refer to like parts wherever they occur,

Fig. l is a Vertical sectional View of a rotary oil burner and combustion chamber therefor, having a hearth construction embodying my invention,

4 Fig. 2 is a similar view of a modified form of hearth construction showing also a different form of distributor head, and

Fig. 3 is a detail view of a further modied form oi hearth.

The hearth construction may be used with any desired form of distributor head and burner construction, the drawings illustrating in Figure 1.

the burner construction shown in my said prior application Serial No. 324,817, and-in Figure 2 a modiiled alternative form. In this construction, a suitable base I provided with adjustable legs 2 has mounted thereon a frame member 3 on which is mounted a stationary electric motor field member t with its winding 5. A frame member 6 above said eld has a at top portion and a depending ange portion' 'i to which is secured the electric motor armature 8. Electric wires 9 in a cable i0 are connected to the field winding 5 and the usual contact making and breaking mechanism Il is provided for split phase motor start- 5 ing purposes.

The armature support 6 is provided with a tubular sleeve i2 that extends axially through bearings i3 in the field supporting frame 3 and into the base, its lower end being supported on an anti-friction step bearing i4.

Secured to the armature support 6 at its top is a hollow shaft i5 at whose upper end is secured a fan or blower I6. The fan comprises a housing whose top or back portion is preferably cupped or dished `and which has depending blades I1 terminating in an end ring i8. A cylindrical sleeve I9 has a hub portion l9a secured to said hollow shaft by a set screw 20, said sleeve extends into the fan inl contact with the inner edges of the fan blades il and thus provides means for varying the amount of air admitted to the fan. Vertical adjustment of the sleeve I9 varies the fan capacity. The connections between the sleeve i9 and the hub i9a are so small as to oier only the slightest resistance to air passing through the sleeve.

An oil feed pipe 2i mounted in the base opens into an oil passageway 22 in said base that is connected to an oil supply pipe 23. Said feed pipe 2i extends through the sleeve l2 of the armature support E and through the hollow shaft l5 at the top of said support, and has openings 26 at its top permitting the escape of oil. Below said openings 24 is a ring 25 that extends radially beyond said shaft, thereby preventing the escape of oil into the motor.

The oil reservoir (not shown in the drawings) is preferably above the level of the burner, so as to dispense with the need for the usual pump. Oil flows from the feed pipe 2l onto the dished back of the air fan i8, whose rotary movement throws the oil outward into the combustion chamber. Said chamber is provided with hearth structure or assembly comprising a iioor or hearth proper 45 of refractory material 26 and around the outer periphery of the combustion chamber is a wall 21 of refractory material having an inwardly proy jecting overhanging flange or ledge 28, so that a l an upwardly and outwardly sloping surface adjacent the ignition pilot 30, which surface assists in preventing the blast of ,air from being projected directly into the protected chamber, as is obvious.

The overhanging ledge 28 of Figure 1 may be provided with vertical openings at intervals, if desired. I

As shown in Fig. 2, the ledge 28 may be provided around its inner periphery with notches or recesses 28a which notches preferably extendnot more than half the distance from the inner edge'of said ledge to the upstandingwall 21. The distributor head of this view includes tubes 50 from which oil is thrown in streams between fan blades 5| that create the air draft.

In the further modification shown in Figure 3, a groove 26a is provided in the hearth floor 26 around the base of the wall 21`and the ledge 28 is provided with vertical openings 28h therethrough.

The oil spray from' the burner head strikes against the wall 21 under the ledge 28, forming a mist. The air stream is caused to move upwardly over the ledge-28, by reason of the blanketing effect of said ledge, and by virtue of the sloping surface formed on the hearth inwardly of the igniter 30, leaving the air and fuel in the recess comparatively undisturbed. This results in quick Y ignition and quick propagation of the flame around the. entire periphery of the hearth. After this propagation of the flame and as the temperature of the hearth rises, the flame moves inwardly and upwardly over the edge of the ledge and' later a large volume of flame is concentrated above the ledge.

It may be desirable to provide for recirculation of the gases in the combustion chamber. In such case, a second fan member 3l is disposed above the air supply fan and secured thereto by suitable pins 32. 'I'he recirculation fan 3| rotates with the air supply fan I6 and causes circulation of the partly consumed gases in the combustion chamber, thereby bringing about a more nearly complete combustion of the fuel. vThe recirculation fan projects above the level of the overhanging ledge so as to draw partly consumed gases from above the level of the annular chamber.

A suitable magnetic control valve, whose housing 33 is shown in the drawings is provided to shut off the flow of fuel when the current to the motor is shut olf. Said valve is of standard construction and is not shown in detail in the drawings. Likewise, any suitable control system may be used and no such system is shown in the drawings.

The above described hearth construction reconciles the conflicting requirements of a protected ignition and propagation zone and a complete draft and supply of air for the working flame, said ame not being conned to the limited propagation zone. Although it is illustrated in connection with two types of burner heads and motor constructions, it will be understood that it is applicable to other types as well. The overhanging ledge provides a protected zone for ignition and propagation of the flame. At the same time, the completed flame is free to project inwardly and upwardly over the ledge, where a' complete supply of air is provided by a draft from the fan. As the hearth becomes more and more heated, the final working flame will be largely concentrated above the ledge. 'I'he ledge servesas a ame retention member to prevent it from lifting too far off the hearth and as a heat conducting member to transmit heat to the wall 21, thus causing the oil to be lvaporized quickly. The flame controlling and retaining function is enhanced by the use of the vertical openwork described above, whether said openwork be in the form of notches 28a as in Figure 2 orof endless holes 28h as in Figure 3.

Obviously numerous changes may be made in the sizes and proportions of the various partsand I do not wish to be limited `to the precise construction shown.

What I claim is:

1. An oil burner construction comprising a combustion chamber having a hearth of refractory material, a continuous wall extending around the periphery of said hearth, a ledge having an imperforate portion projecting inwardly from the upper portion of said wall and materially overhanging the hearth, and rotary means for spraying oil into said combustion chamber below the level of the overhanging portion of said ledge member. f

2. An oil burner construction comprising a combustion chamber having a hearth of refractory material, an imperforate wall of refractory material extending around the entire periphery of said hearth, a ledge member having an im- Y perforate portion of refractory material projectspraying oil into said combustion chamber below the level of the overhanging portion of said ledge member.

4. In a liquid fuel burning apparatus, a subi stantially horizontal hearth, an upright wall mounted upon the hearth, a fuel and air projector disposed just above the hearth level in spaced relation to'said wall to throw fuel into impingement with said wall, and a substantially horizontal ledge provided with an imperforate roof portion, said roof portion forming with said wall a substantially continuous and unbroken surface that projects away from the wall materially in the direction of said fuel and air projector; whereby said hearth, said wall and said roof portion cooperate to form a protected zone for initial ame propagation. f

5. The apparatus defined in claim 4, said ledge having a. conterminous edge portion extending beyond said imperforate roof portion in the direction of the projector and provided throughout its length with vertical openings, whereby said ledge serves to hold the propagated flame down toward the hearth.

6.. In a liquid fuel burning apparatus a combustion chamber having a hearth structure and a rotary fuel and air distributor mounted substantially at the center of the hearth structure said hearth structure including a peripheral structure arranged relatively remote from said distributor and at approximately the same level, said peripheral structure having an upright fuel impact wall and forming a sheltered ignition zone, and said hearth structure being provided with a sloping'surface adjacent said wall, the degree of slope being such that if the surface were projected outwardly it would intersect the peripheral structure adjacent the top of said sheltered ignition zone.

7. In a liquid fuel burning apparatus a substantially horizontal hearth structure having a floor, an upright wall mounted upon the floor and a fuel and air projector located just above the floor in spaced relation to said upright wall, for projecting fuel into impingement with said wall and for projecting a blast of air along the floor surface toward said wall, said hearth structure being provided with a gutter at the bottom of said upright wall. and a llame-controlling structure adjacent the top of said wall and overhanging said gutter; the floor surface being relatively smooth and without abrupt changes in shape, and comprising a substantially flat portion terminating at the top of said gutter.

t. In a liquid fuel burning apparatus a combustion chamber having a hearth, and a rotary fuel and air distributor mounted substantially at the center oi said hearth to create a flow of fuel and air adjacent the hearth toward the hearth periphery; a peripheral structure on the hearth surrounding said distributor in substantially radially spaced relation thereto, said structure having an upright fuel impingernerit wall, and means cooperating with said wall to form a substantially annular sheltered dame propagation zone, said sheltered zone being located adjacent the vertex of the angle formed between said impingement wall and the hearth surface.

Q. In a liquid fuel burning apparatus a corn-l loustion chamber having a distributor arranged approximately at the center of the bottom of said chamber and projecting blasts of liquid fuel and air substantially horizontally, in radial ection; a. hearth assembly closing the bottom of sciiti chamber and including a. fuel irnpingernent wall outvifardly spaced from said distributor; seaid assembly further including an air deilecting surface located inwardly trom said impingement wall cooperating with the latter to form an elonperipheral sheltering zone that is protected from the air blast, and an ignition device having a ilameuproducing portion located within said sheltered zone between said deflecting surface the lower portion of said impingement Wall.

it?. lin oil burner construction comprising a eoinhustioh chamber having a hearth oi retractorfy material, a continuous Wall of refractory tire periphery of said hearth, a continuous ledge member of refractory material projecting' inwardly from the upper portion of said wall and overhanging saidl hearth-to form with said wall and said hearth a three-sided sheltered chamber,

the inner edge portion of said ledge comprising an open-work structure, and means for spraying oil into said combustion chamber below the level of the overhanglng portion' of said ledge member.

l1. An oil burner construction comprising a hearth of refractory material, a continuous wall of refractory material extending upwardly and around the periphery ofsaid hearth and having a continuous ledge extending inwardly above the hearth periphery, said hearth having a peripheral groove at the base of said wall underneath said ledge, and means for spraying oil toward said wall below the level of said overhanging ledge.

l2. In a liquid fuel burning apparatus, a substantially horizontal hearth structure having an upper surface and including an upright wall mounted above said surface, a fuel and air prolector located just above said surface in spaced relation to said upright wall, for projecting fuel into impingement with said wall and for projecting a blast of air along said surface toward said Wall, said surface having an upwardly, outwardiy sloping portion disposed inwardly trom said upright wall, and an ignition device having a flame-producing portion disposed below the outward extension of said sloping portion of said material extending upwardly and around the ensurface and adjacent the hottorn of the upright wall.

it. In a liquid fuel burning apparatusa combustiou chamber, a distributor disposed substantially centrally of the chamber and constructed to project liquid fuel outwardly and to discharge an air blast outwardly below the projected fuel, an

upright impingement wall located outwardly from 4 MHITON A. PUVMRS. 

